1. Field of the Invention
The present invention relates to an apparatus for processing image information provided with a recording unit for forming ink images and other image information on a sheet medium by use of ink or a reading unit for reading image information formed on the surface of a sheet medium such as a source document. More particularly, the invention relates to the structure of an electric board used for the apparatus for processing image information.
2. Related Background Art
As an apparatus for processing image information, there has been a printer provided with a recording unit for forming ink images on a sheet medium by use of ink, a scanner provided with a reading unit for reading image information represented by ink or the like on the surface of a sheet medium such as a source document, or an apparatus provided with both of them for recording on a sheet medium the image information as it has been read by a reading unit or after having been processed by use of a recording unit.
Then, as an apparatus for processing image information, a facsimile apparatus is known.
For facsimile apparatuses, there are those which use an ordinary sheet, a thermo-sensitive sheet, or the like as a recording medium (sheet medium) for recording to be made on by use of the recording system of the apparatus. In recent years, a facsimile apparatus using an ordinary sheet begins to be used more widely in consideration of the easier preservation of sheets, shareability with other apparatuses such as copying machine, lesser degree of presenting environmental problems, among other advantages obtainable by the use of ordinary sheets. Of such facsimile apparatus, the one provided with recording systems of ink jet type attracts particular attention because of the advantages that the facsimile apparatus of this type can be fabricated compactly at lower costs.
FIG. 15 shows a conventional facsimile apparatus described above. The fundamental structure of the facsimile apparatus shown in FIG. 15 is: an operational unit 101 having various keys; a reading unit 102 which reads information while feeding a source document; a recording unit 103 for recording such information on a recording sheet; and an electric board 104 forming control systems for controlling the entire system of the apparatus and others, in that order from above.
The operational unit 101 is provided with an operating board 101c having tact switches 101a for various keys and an LCD 101b and others functioning as an indicating unit assembled on it. The reading unit 102 is provided with a sensor 102a for sensing the presence and absence of a source document, and a document edge sensor 102b for detecting the edges, such as the leading and trailing ends, of a source document, in addition to means such as rollers for feeding a source document, and means for reading information from the source document. The recording unit 103 is provided with a roller sensor 103b for detecting one rotation of a pickup roller 103a, a sheet edge sensor 103c for detecting the leading and trailing ends of a recording sheet, and a footer sensor 103d for recording a pattern on a recording sheet in order to detect its density for determining ink remains and any existence of jamming, in addition to feeding means such as rollers, and recording means (head cartridge 103e) for recording information on the recording sheet. The electric board 104 comprises a control board 104a constituting a controller for controlling the operation of the apparatus, a line net control board 104b which constitutes a line net controller for controlling the line relations, and a power source board 104c having the main power-supply.
Then, for each of the sensors 102a, 102b, 103b, 103c, and 103d, its board and harness are arranged to connect it to the control board 104a after being drawn around inside the apparatus.
Also, for the recording unit (recording apparatus) for a facsimile apparatus, copying machine, printer, or the like, each serving as an apparatus for processing image information, there is adopted a system having a recording head mounted on a carriage for performing recording by allowing it to travel serially in the direction different from the sheet feeding direction. The structures adopted for the electric circuit board of the controlling system of such recording apparatus are roughly divided into two kinds as given below.
1) A comparatively large-sized electric circuit board such as used for a large printer and facsimile apparatus, or a board which is arranged for an apparatus whose size itself is large. In a recording apparatus of this type, a part (that is, a first electric circuit board) of the electric circuit board to control the recording apparatus is arranged on the plane in the vicinity of a carriage including lines parallel to the traveling direction of the carriage, and then, this board and the main control electric circuit board (a second electric circuit board) are connected by means of bundled wires.
2) A comparatively small-sized electric circuit board such as used for a printer or arranged for an apparatus whose size itself is small. For a recording apparatus of the type, a small electric board (that is, a first electric circuit board) to control the recording apparatus is arranged in a plane in the vicinity of a carriage including lines parallel to the traveling direction of the carriage.
The first electric circuit boards of the structures referred to in the preceding paragraphs 1) and 2) are comparatively small-sized, and are formed in half a width or less than a half the width of the traveling range of the carriage. Therefore, the flexible cable which connects the recording head and the first electric circuit board can be connected to the assembling surface of the board formed on the side opposite to the carriage through the side face of the board without standing in the way if only the first electric circuit board should be arranged close to one side.
In this case, what is most important is the length of the cable and the path through which it is connected. In a apparatus having a system of serial traveling, the above-mentioned flexible cable is generally structured as follows:
At first, The flexible cable is a wiring element of a sandwiched structure, that is, the element is finely produced by depositing or adhesively bonding a conductor on a high-quality resin film of polyimide or the like, and then, it is further covered by the film.
Consequently, this cable is made characteristic in that 1) being flat, the cable can be bent uniformly in the direction at right angles to the plane (thus often used as a connecting cable to the carriage), and 2) cost per length is high (but for a comparatively short wiring, the cost becomes lower as compared with the bundled wires usually used to the extent that the connector generally required on the wire side can be omitted by this cable arrangement). Here, although the cable can be formed arbitrarily in any shape, it may easily cost more depending on the process requirements for its manufacture.
Now that the carriage scans in the main scanning direction, the flexible cable which is connected to the carriage should be clamped by means of a chassis or the like which is fixed substantially in the central portion of the traveling range of the carriage, and then, should be drawn further around to connect it to the first electric circuit board described above. This arrangement is necessary in order to make the length of the flexible cable shorter, and also, to prevent the flexible cable from being projected largely outside the traveling range of the carriage when the cable is in excess.
Also, with the structure described in the paragraph 2), the width of the board cannot be but approximately half the traveling range of the carriage if it is used for a facsimile apparatus or the like which is provided with a comparatively large-sized electric circuit board. In this case, it is inevitable that its height should be made greater in order to obtain a required area, thus necessitating to make the apparatus larger as a whole (such being the case, this is not adopted for a facsimile apparatus eventually). Also, if the first electric circuit board is made smaller in its height while expanding its width to cover the entire traveling range of the carriage, it is inevitable that the flexible cable should be drawn long to be connected to the assembling surface along the reverse side (soldering end) of the first electric circuit board. As a result, this arrangement tends to allow the system to be easily affected by noises, and also, results in a higher cost of manufacture.
Also, in the conventional example described above, many numbers of boards (operating board, control board, net control board, board for each of the sensors, and the like) are present, while these boards should be connected by wires. Many numbers of harnesses are to be drawn in the interior of the apparatus main body, hence leading to the disadvantages such as lowered assembling capability, increased costs, degraded quality, and confined structural conditions.
Also, in the conventional example described above, the boards should be connected to one another with the passage planes of a source document and a recording sheet, which are sandwiched by the boards from above and below; thus making it necessary for the harnesses to avoid standing in the way of the passage planes of the document and sheet. Also, the harnesses thus connected tend to serve as antenna to generate a considerable amount of emitting noises. Hence there is a fear that a radio or television receiver nearby is affected by such noises.
Also, in the structures 1) and 2) of the conventional recording apparatus described above, the following problems are encountered:
At first, in the structure described in the paragraph 1), the bundled wires are used to connect the first electric circuit board, which is arranged in the vicinity of the carriage, with the second electric board long way from the first board. Therefore, it is easier to pickup noises. At the same time, there are often needed various kinds of sensors to be arranged on the sheet feeding path, such as a sensor for detecting the sheet presence and absence, a sheet edge sensor. In this case, it should be desirable to assemble these sensors on the first electric circuit board to be arranged in the vicinity of the carriage in consideration of the space efficiency, assembling capability, and cost performance. In the conventional apparatus, therefore, the number of bundled wires which connect the first and second electric circuit boards is also increased accordingly, thus making it easier to pickup noises.
Also, in order to meet the requirements with respect to the maintenance of recording head, and replacement of disposable heads, the structure of the recording apparatus should desirably be arranged as a whole to provide the carriage on the upper face side (or in the direction toward the front face) of the apparatus, and the sheet feeding path and sheet feeding means on the lower face side (or in the direction toward the rear face) of the apparatus, respectively. In this case, the second electric circuit board which is arranged away from the carriage should desirably be arranged further below the sheet feeding path and sheet feeding means. This is because the second electric circuit board described above not only hinders the execution of the recording head maintenance and replacement of disposable heads, but also makes it difficult to structure the operational panel of the apparatus, among other drawbacks. In this case, the sheet feeding path is present between the first electric circuit board arranged in the vicinity of the carriage and the second electric circuit board.
In other words, the bundled wires which connect the first and second electric circuit boards should detour the sheet feeding path to a considerable extent. This unfavorably brings about a further mixture of noises. Also, the longer the bundled wires, the more the costs are increased. Also, on the subject of costs, the first electric circuit board arranged in the vicinity of the carriage is as if to function as a relaying board in this respect, which fundamentally constitutes an excessive part, a factor which results in an increase in costs.
Also, from the viewpoint of costs, even if a flexible cable is drawn around to make a direct connection with the second electric circuit board without using such relaying board, the cable should be made longer or there should be a need for the provision of a cable of different type. This will also ensure in an increased cost.
Also, it becomes impossible to sufficiently utilize the vicinity of the large area which should be used for the carriage traveling, thus necessitating the provision of a space separately for a large electric circuit board. This definitely lowers the space efficiency.
Also, in a case of the apparatus for processing image information which is provided with a recording unit (recording apparatus) of ink jet type, it is necessary for the electric board 104 to be shielded by use of an ink absorbing sheet or the like as a preventive measure against any ink leakage if the electric board 104 (control board 104a, net control board 104b, and power-supply board 104c) is to be arranged below the ink discharge ports 103f of the recording head 103e in the recording unit 103 as in the conventional example, because ink is conductive as well known. However, since many numbers of harnesses are drawn around for connection of the electric board 104 as described earlier, the provision of such shielding means requires an extremely complicated work. Also, there is a need for providing holes for the harnesses to pass through, thus making perfect shielding impossible, among other problems.